Armada was a sci-fi shooter released for the Dreamcast, that allowed 1-4 players to fly about the universe, fighting the enemy, performing missions and improving their ship. The player would gather credits to buy power-ups for their ship, allowing them to voyage deeper into enemy territory, blow up ever more powerful Armada, and perform missions of increasing importance and danger.
A sequel, Armada 2: Exodus, was under development, originally for the Dreamcast, then for the Xbox, Gamecube and possibly the PS2. However, due to repeated delays and redesigns along with limited resources, the game was canceled after spending over 4 years in varying degrees of development. [Infos from Wikipedia]